// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/download/rate_estimator.h"

#include "testing/gtest/include/gtest/gtest.h"

using base::TimeDelta;

namespace content {

TEST(RateEstimatorTest, RateEstimator)
{
    base::TimeTicks now;
    RateEstimator estimator(TimeDelta::FromSeconds(1), 10u, now);
    EXPECT_EQ(0u, estimator.GetCountPerSecond(now));

    estimator.Increment(50u, now);
    EXPECT_EQ(50u, estimator.GetCountPerSecond(now));

    now += TimeDelta::FromMilliseconds(800);
    estimator.Increment(50, now);
    EXPECT_EQ(100u, estimator.GetCountPerSecond(now));

    // Advance time.
    now += TimeDelta::FromSeconds(3);
    EXPECT_EQ(25u, estimator.GetCountPerSecond(now));
    estimator.Increment(60, now);
    EXPECT_EQ(40u, estimator.GetCountPerSecond(now));

    // Advance time again.
    now += TimeDelta::FromSeconds(4);
    EXPECT_EQ(20u, estimator.GetCountPerSecond(now));

    // Advance time to the end.
    now += TimeDelta::FromSeconds(2);
    EXPECT_EQ(16u, estimator.GetCountPerSecond(now));
    estimator.Increment(100, now);
    EXPECT_EQ(26u, estimator.GetCountPerSecond(now));

    // Now wrap around to the start.
    now += TimeDelta::FromSeconds(1);
    EXPECT_EQ(16u, estimator.GetCountPerSecond(now));
    estimator.Increment(100, now);
    EXPECT_EQ(26u, estimator.GetCountPerSecond(now));

    // Advance far into the future.
    now += TimeDelta::FromSeconds(40);
    EXPECT_EQ(0u, estimator.GetCountPerSecond(now));
    estimator.Increment(100, now);
    EXPECT_EQ(100u, estimator.GetCountPerSecond(now));

    // Pretend that there is timeticks wrap around.
    now = base::TimeTicks();
    EXPECT_EQ(0u, estimator.GetCountPerSecond(now));
}

} // namespace content
